In many high-performance applications, two exemplary competing design parameters of A/D converters are speed and resolution. Many designs for A/D converters have been proposed which include deterministic A/D converters and sequential A/D converters. Each of the proposed designs has its own merits and disadvantages. Deterministic A/D converters receive an analog input and produce an output after a delay. Sequential A/D converters use feedback, RC charging, or other such methods and require several internal steps to generate the digital output. Further details regarding deterministic and sequential A/D converters can be found in Sedra and Smith, Microelectronic Circuits (4th Edition), Oxford University Press, pages 864–870, the details of which are incorporated herein by reference in their entirety.
Sequential A/D converters can generate high precision conversions and can allow for high resolutions. Examples of such topologies include feedback-type, delta-sigma type, dual-slope and charge redistribution. Such topologies generally trade speed for precision.
Deterministic A/D converters are generally high speed devices, and lack the precision of the sequential devices. For example, the highest deterministic A/D resolutions are generally found to be of 8-bits. Such A/D converters are considered deterministic since other than for control of track/hold functionality, there is no control logic, clocking, or iterative, series comparisons. Such A/D converters simply produce the digital output from the received input. Two principal topologies of these devices are, for example, folding and flash type designs. Both are high speed implementations and are further discussed below.
Accordingly, there is a need to overcome the above-identified problems.